Method of regulating plant growth

ABSTRACT

The method is suitable for improving the growth of a range of target plants, in particular improving the growth of sugarcane, rice, soybeans, oilseed rape and potato crops.

The present invention relates to a method of regulating the growth ofplants, in particular for improving the growth of the target plants.

Various methods of regulating the growth of target plants, in particularto improve plant growth, are described in the literature. These methodsare typically based on conventional fertilizing. The biological effectsof those known methods are not entirely demonstrated in the agriculturearea. Thus, there is a high demand in the agricultural industry toprovide techniques to improve the growth of the desired plants, inparticular for obtaining higher crop yields, as well as the reduction ofthe use of the quantity of fertilizers needed to be applied to thetarget plants to improve their growth and yields.

It is known that certain isoxazolidinones are active as herbicides andare useful in the control of unwanted plant growth. One particularisoxazolidinone of commercial importance is2-(2-chlorophenyl)methyl-4,4-dimethyl-3-isoxazolidinone, known in theart and referred to hereinafter by the common name clomazone. Theherbicidal active compound clomazone is known from U.S. Pat. No.4,405,357 and is generally used to control weeds and unwanted plantgrowth in various crops. Clomazone is a compound having the generalformula (I).

Clomazone is known to be a very volatile organic compound. Inparticular, the volatility of the compound is such that, once applied toplants in a target area can move to adjacent areas outside of the targetarea. As a result of this movement or drift to non-target areas, plantsin those areas may suffer damage as a result of the effects ofclomazone. In particular, clomazone can cause discoloration of thefoliage, most typically whitening or some degree of bleaching, of avariety of crops, trees, or decorative plants. This bleaching may betemporary when the plants are exposed to sufficiently low concentrationsof clomazone. Nevertheless, it is undesirable, even when not causing thedestruction of the affected plant. At higher concentrations, the plantsmay be permanently damaged or even killed.

As a result, appropriate instructions for the handling and use ofclomazone are typically found on product labels of commerciallyavailable clomazone products, in particular on emulsifiable concentrate(EC) formulations comprising clomazone, in order to limit or preventexposure of sensitive plants in non-target areas to potentially damagingconcentrations of clomazone.

As a result of the high volatility of clomazone and the resultantproblems in handling and applying clomazone-containing formulations inthe field, techniques have been developed to reduce or prevent the driftof clomazone once applied to a target locus. In particular, techniquesof formulating clomazone to reduce its volatility, thereby to reduce orprevent vapor transfer of clomazone to plants which are not the targetof application have been proposed in the art. For example, U.S. Pat.Nos. 5,597,780 and 5,583,090 describe encapsulation techniques, in whichmicrocapsule suspension formulations of clomazone are prepared. Similarformulations comprising microencapsulated clomazone, their preparationand use are disclosed in European Patent Application publication Nos. EP1 840 145 and EP 2 487 192.

Clomazone is known to be active as a broad spectrum herbicide with itsability to control annual grasses and broadleaf weeds in various crops.It has now surprisingly been discovered that clomazone is active inimproving the growth of target plants.

Accordingly, according to the present invention there is described amethod for improving the growth of target plants at a locus, the methodcomprising applying to the locus a growth-improving amount of compound(I):

It has now been found that the application of compound (I) can result inan improvement of the growth of the plant. In this respect, the growthof a plant is considered to have improved growth if it exhibits at leasta 10% improvement or increase in one or more of earlier emergence, cropyields, more developed root system, plant height, bigger leaf blade,increased shoot growth, and improved plant vigor, and/or at least a 10%decrease in the amount of fertilizer or a 10% decrease in the number ofseeds required to achieve a predetermined crop yield from the locus. Inthis respect, a growth-improving amount of clomazone is to be understoodaccordingly as an amount of clomazone required to achieve theaforementioned improvement in growth of the target plants.

The clomazone may be applied to the target plants with the locus in anysuitable condition. Especially preferred is the use of the clomazone inthe method for the improvement of the growth of the target plants whichare essentially free of weeds, more particularly essentially free ofannual grasses and broadleaf weeds.

A further aspect of the invention there is provided the use of compound(I) for improving the growth of target plants at a locus.

Crops which can be improved according to the method of the presentinvention include cereals, such as wheat, barley, rye, oats, rice, maizeand sorghum; beet, such as sugar beet and fodder beet; fruit, forexample pomes, stone fruit and soft fruit, such as apples, pears, plums,peaches, almonds, cherries and berries, e.g. strawberries, raspberriesand blackberries; leguminous fruits, such as beans, lentils, peas andsoybeans; oil plants, such as oilseed rape, mustard, poppy, olives,sunflowers, coconut, castor oil plants, cocoa beans and groundnuts;cucurbitaceae, such as marrows, cucumbersand melons; fibre plants, suchas cotton, flax, hemp and jute; citrus fruit, such as oranges, lemons,grapefruit and mandarins; vegetables, such as spinach, lettuce,asparagus, cabbages, carrots, onions, tomatoes, potatoes and paprika;lauraceae, such as avocados, cinnamon and camphor; and also tobacco,nuts, coffee, aubergines, sugar cane, tea, pepper, vines, hops, bananas,natural rubber plants and ornamentals; especially sugarcane, rice,beans, soybeans, oilseed rape and potatoes.

It has been found that the present invention is particular advantageousin improving the growth of sugarcane, rice, soybeans, oilseed rape andpotato crops.

As noted above, in the method of the present invention, the growth ofthe target plants at the locus is improved by applying to the locus acomposition comprising clomazone. Clomazone may be applied to the locusin any suitable composition or formulation. Clomazone is preferablyapplied to the locus together with at least one adjuvant. The adjuvantscustomarily used in the formulation of agrochemical products are wellknown in the art and understood by the person skilled in the art.Suitable adjuvants include such components as extenders, for examplesolvents or solid carriers, stabilisers, slow-release adjuvants, dyesand one or more surface-active substances (surfactants). Suitablecarriers and adjuvants in this case include all substances customarilyused in the formulation of crop protection products, especially inproducts for controlling plant growth. Suitable adjuvants, such assolvents, solid carriers, surface-active compounds, non-ionicsurfactants, cationic surfactants, anionic surfactants and furtheradjuvants in the compositions used in accordance with the invention are,for example, the same as those described in EP 0 736 252.

The preparation and use of suitable clomazone formulations are known inthe art and clomazone formulations are commercially available. Examplesof suitable clomazone formulations include emulsifiable concentrates(EC), suspension concentrates (SC), directly sprayable or dilutablesolutions, coatable pastes, dilute emulsions, wettable powders (WP),soluble powders, dispersible powders, dusts or granules. In a preferredembodiment, clomazone is present in the formulation in an encapsulatedform, that is an encapsulation in polymeric substances. As noted above,such microencapsulated forms of clomazone are known in the art.

As noted above, a preferred embodiment of the present inventioncomprises applying to the locus to be treated clomazone in amicroencapsulated form. Formulations comprising microencapsulated activeagrochemical components, in particular clomazone, are known in the artand are commercially available. The microencapsulated clomazonecomprises microcapsules having a polymer shell and a core, the corecontaining clomazone, optionally with one or more other components, suchas a solvent and other adjuvents or excipients typically employed inagrochemical formulations. The polymer shell may be of any suitablepolymer material and the microcapsules formed by any suitable method.Preferably, the polymer shell is formed using an interfacialpolymerisation technique. Examples of suitable polymers includepolyamides, polyesters, polyurethanes and polyureas. The polymer ispreferably a polyurea, in particular a polyurea formed from the reactionof one or more isocyanate compounds and one or more amine compounds.Such reactions are known in the art and the reactants known andcommercially available.

Examples of microencapsulation suitable for use in preparing theclomazone for inclusion in the granules of the present invention aredisclosed in EP 0 719 087, EP 0 792 100, EP 0 854 675, EP 1 104 991, EP1 164 849, EP 1 404 176, EP 1 928 593, EP 2 133 140, WO 01/24631, WO03/099005, WO 96/22159, WO 2007/072046, WO 2007/101019, WO 2009/00545,and WO 2009/086914.

An example of a formulation of a microencapsulated form of clomazone ingranules suitable for use in the present invention is disclosed inUnited Kingdom Patent No. GB 2478317.

The clomazone composition may comprise further components, in additionto those discussed above. Examples of such components include thosecomponents commonly included in agrochemical formulations and includeone or more components selected from biocides, adjuvants, and activitymodifiers, including safeners and synergising agents of the activeingredients. Such components are commercially available and their use isknown in the art.

The clomazone composition may comprise any suitable amount of clomazone,sufficient to allow a growth-improving amount of clomazone to the targetlocus. The composition may contain clomazone in an amount of from 0.1 to99% by weight, more especially from 0.1 to 95%.

Whereas commercial products will preferably be formulated asconcentrates, the end user will normally employ dilute formulationswhich have considerably lower concentrations of clomazone, for exampleby diluting or dispersing the clomazone formulation in a suitablecarrier, in particular water.

The rate at which clomazone is applied to the locus being treated is atleast sufficient to obtain an improvement in the growth of the targetplants at the locus, as indicated above. This rate may be in the rangeof from 0.01 to 3.0 kg/hectare, more preferably from 0.05 to 2.0kg/hectare, still more preferably from 0.05 to 1.5 kg/hectare, providedthat the improvement in the growth of the target plants is obtained.

Clomazone may be the sole active ingredient present in the compositionapplied to the locus. Alternatively, clomazone may be present incombination with one more other active ingredients. Compatible activecomponents that may be applied together with clomazone to the locusinclude one or more other herbicides, insecticides, fungicides,nematocides, plant growth regulators, and/or safeners. Suitable activecomponents are known in the field and are available commercially. Theymay be formulated with clomazone using techniques known in the art.

As noted above, it has been found that target plants at the locusexhibit improved growth as a result of treatment with clomazone.Accordingly, the benefit of the present invention may be realized byreducing the amount of fertilizer applied to the locus, while stillachieving the same growth characteristics of the target plants. Thereduction in fertilizer may be at least 10% by weight.

The method of treating plants and the use of clomazone of the presentinvention are described, for illustrative purposes, by way of thefollowing examples.

EXAMPLES Example 1

Sugarcane plants are treated by the application of a commerciallyavailable concentrate formulation of clomazone (Centium 360 CS®; asuspension concentrate of microencapsulated clomazone at a concentrationof 360 g/l). The concentrate formulation is dispersed in water anddiluted, in a manner conventional in the art, to give an aqueous spraycomposition. The spray composition is applied to the sugarcane plants inan amount to apply clomazone at a rate of 120 g/hectare.

The growth of the sugarcane plants is monitored and compared with thegrowth of sugarcane plants grown under the same conditions, but withouttreatment with clomazone.

It is observed that the growth of the treated sugarcane plants issignificantly improved, in comparison to the untreated plants, inparticular with the treated plants exhibiting a larger average leafblade area, increased shoot growth and growing to a greater averageheight.

Example 2

Young rice plants are treated in an analogous manner to that describedin Example 1.

The growth of the rice plants is monitored and compared with the growthof rice plants of the same age and grown under the same conditions, butwithout treatment with clomazone.

It is observed that the growth of the treated rice plants issignificantly improved, in comparison to the untreated plants, inparticular with the treated plants exhibiting a larger average leafblade area, increased shoot growth and growing to a greater averageheight.

Example 3

Young soybean plants are treated in an analogous manner to thatdescribed in Example 1.

The growth of the soybean plants is monitored and compared with thegrowth of soybean plants of the same age and grown under the sameconditions, but without treatment with clomazone.

It is observed that the growth of the treated soybean plants issignificantly improved, in comparison to the untreated plants, inparticular with the treated plants exhibiting a larger average leafblade area, increased shoot growth and growing to a greater averageheight.

Example 4

Young oilseed rape plants are treated in an analogous manner to thatdescribed in Example 1.

The growth of the oilseed rape plants is monitored and compared with thegrowth of oilseed rape plants of the same age and grown under the sameconditions, but without treatment with clomazone.

It is observed that the growth of the treated oilseed rape plants issignificantly improved, in comparison to the untreated plants, inparticular with the treated plants exhibiting a larger average leafblade area, increased shoot growth and growing to a greater averageheight.

Example 5

Young potato plants are treated in an analogous manner to that describedin Example 1.

The growth of the potato plants is monitored and compared with thegrowth of potato plants of the same age and grown under the sameconditions, but without treatment with clomazone.

It is observed that the growth of the treated potato plants issignificantly improved, in comparison to the untreated plants, inparticular with the treated plants exhibiting a larger average leafblade area, increased shoot growth and growing to a greater averageheight.

The invention claimed is:
 1. A method for improving the growth of targetplants at a locus, the method comprising the steps of: a) preparing agrowth improving composition having a growth improving compoundconsisting essentially of compound (I) and wherein compound (I) ismicroencapsulated and the only herbicide in the composition

b) applying the growth improving composition of step a) directly to apost-emergent target plant selected from the group consisting of corn,bean, soybean, oilseed rape, potato, and mixtures thereof, the targetplant being free of annual grasses and broadleaf weeds at the time ofapplication, and applying at the locus in an amount ranging from 0.05 to1.5 kg/hectare wherein said amount applied is sufficient to cause anincrease of at least 10%, compared to an untreated target plant, in anaverage value of at least one measure of the target plant selected fromthe group consisting of crop yield, root system size, leaf blade area,shoot growth, plant height, and mixtures thereof.
 2. The methodaccording to claim 1, further comprising applying to the locus at leastone additional compound selected from the group consisting ofinsecticides, fungicides, nematocides, and/or safeners in addition tothe growth improving composition of step a).
 3. The method according toclaim 1, wherein an amount of fertilizer applied to the locus is reducedby at least 10% by weight from the amount that would be applied toachieve the same plant growth without treatment with the growthimproving composition containing compound (I).
 4. A method for improvingthe growth of target plants at a locus, the method comprising the stepsof: a) preparing a growth improving composition comprising compound (I),wherein compound (I) is the only herbicide in the composition andwherein compound (I) is microencapsulated

b) applying the growth improving composition of step a) directly to apost-emergent target plant selected from the group consisting of corn,bean, soybean, oilseed rape, potato, and mixtures thereof, the targetplant being free of annual grasses and broadleaf weeds at the time ofapplication, and applying at the locus in an amount ranging from 0.05 to1.5 kg/hectare wherein said amount applied is sufficient to cause anincrease of at least 10%, compared to an untreated target plant, in anaverage value of at least one measure of the target plant selected fromthe group consisting of crop yield, root system size, leaf blade area,shoot growth, plant height, and mixtures thereof.
 5. The methodaccording to claim 4, further comprising applying to the locus at leastone additional compound selected from the group consisting ofinsecticides, fungicides, nematocides, and/or safeners in addition tothe growth improving composition of step a).
 6. The method according toclaim 4, wherein an amount of fertilizer applied to the locus is reducedby at least 10% by weight from the amount that would be applied toachieve the same plant growth without treatment with the growthimproving composition containing compound (I).
 7. The method accordingto claim 4, wherein the composition of step a) further comprises atleast one adjuvant comprising an extender, a stabilizer, a slow-releaseadjuvant, a dye, a surfactant, or mixtures thereof.
 8. A method forimproving the growth of target plants at a locus, the method comprisingthe steps of: a) preparing a growth improving composition comprisingcompound (I), wherein compound (I) is microencapsulated, the only activegrowth improving component in the composition and the only herbicide inthe composition

b) applying the growth improving composition of step a) directly to apost-emergent target plant selected from the group consisting of corn,bean, soybean, oilseed rape, potato, and mixtures thereof, the targetplant being free of annual grasses and broadleaf weeds at the time ofapplication, and applying at the locus in an amount ranging from 0.05 to1.5 kg/hectare wherein said amount applied is sufficient to cause anincrease of at least 10%, compared to an untreated target plant, in anaverage value of at least one measure of the target plant selected fromthe group consisting of crop yield, root system size, leaf blade area,shoot growth, plant height, and mixtures thereof.
 9. The methodaccording to claim 8, further comprising applying to the locus at leastone additional compound selected from the group consisting ofinsecticides, fungicides, and nematocides in addition to the growthimproving composition of step a).
 10. The method according to claim 8,wherein the composition of step a) further comprises at least oneadjuvant comprising an extender, a stabilizer, a slow-release adjuvant,a dye, a surfactant, or mixtures thereof.